1. Field of the Invention
The present invention relates generally to window regulators and more specifically to an improved cable type window regulator.
2. Brief Description of the Prior Art
In a known arrangement shown in FIG. 1, a window glass 1 has been raised and lowered using a crank arm 2 driven by a suitable manually operated mechanism 3. This arrangement, while being sturdy has suffered from the drawback of being heavy and increasing the thickness of the door 4 (especially that portion indicated in FIG. 2 by "L") in which it is disposed due to the inherent bulk of the winder and arm mechanism. In order to solve both of the weight and the thickness problems it has been subsequently proposed to use a cable type regulator 5 such as shown in FIG. 3. However, this arrangement has suffered from a notable lack of stability and a resulting very jerky operation. Accordingly, various stabilizing measures such as proposed in Japanese Patent Application "Tokkosho 50-17733" have been employed. These stablizing arrangements are shown in FIGS. 6 to 9. In each of these arrangements, a stationary guide rail 6 is fixedly secured to a slotted tube 7 in which a cable 8 having a helical ridge is slidably disposed. A movable bracket 9 is fixedly connected to the cable 8 by an extension thereof which passes through the slot in the tube 7. Blocks 10 are mounted on the bracket 9 and located so that slits 11 formed therein slidably receive the edges of the guide rail. The bracket 9 is also fixedly connected to the window glass so that upon the cable being moved within the tube via rotation of a handle 12, which drives a gear wheel 13 arranged to mesh with the helical ridge of on the cable 8 (see FIG. 4), the window glass is accordingly raised or lowered along a predetermined path 14 (shown in phantom in FIG. 5).
However, these arrangements have still been unable to provide the desired degree of rigidity and resulting smooth jerk-free sliding stability while simultaneously inducing a further problem that the mass production of the regulator having these kind of stabilizers is difficult. That is to say, in these previously proposed arrangements, as the guide rails 6 have been formed from relatively thin and accordingly flexible sheet steel or the like (to minimize weight), the blocks 10 which slide on the rails are required to be formed with correspondingly narrow slits 11. These narrow slits apart from being difficult to cut within the required close tolerances so as to fit rattle free on the guide rail or rails, also require that during assembly, the blocks in which they are formed be very accurately located so as to ensure proper alignment of the slits with the portions of the guide rails which are received therein. All of this complicates production increasing the overall cost of the final product while still not providing satisfactory operational characteristics.